The photo-messaging service, which is wildly popular with teens, unleashed a big update on Thursday that drove its young users to distraction and disrupted classrooms.

Snapchat, launched in 2011, lets users send photo messages that vanish after just a few seconds. The latest update includes a much-anticipated “chat” feature that lets kids text or video chat with their friends.

Those messages also automatically self-destruct once the chat is complete.

Apparently, Snapchat’s target demo was so desperate to download the latest version that it created havoc during the school day.

“In 16 years of teaching I can’t think of anything that has ever disrupted my classroom more than today’s @snapchat update,” tweeted Tracie Schroeder, a teacher at Council Grove High School in Kansas.

High school teacher: In 16 years of teaching, nothing has disrupted my classroom more than Snapchat's new update http://t.co/kFMOupn9L2

Schroeder, who likened the addictive app to “crack,” said she had to take away her students’ phones.

“I have no idea what all was included in the update, but you would have thought it was crack,” she said in an interview with Silicon Alley Insider, a tech blog. “They seriously could not keep away from it. I even had one girl crawl under the table with her phone.”

Former Mayor Mike Bloomberg banned cellphone use in New York City public schools.

Even before the latest update, Snapchat has generated controversy, with critics saying it is mostly used for “sexting.”